In the production of fluids from subterranean formations, it has been a long-standing practice to hydraulically fracture the formation from a wellbore to enhance the flow of fluids from the formation into the wellbore. Hydraulic fracturing is typically employed to stimulate wells which produce from low permeability formations.
During hydraulic fracturing, a fracturing fluid is injected into the wellbore at high pressures to create fractures in the rock formation surrounding the bore. The fractures radiate outwardly from the wellbore, typically from a few to hundreds of meters, and extend the surface area from which oil or gas drains into the well.
In the absence of suitable boundaries, it is not uncommon during hydraulic fracturing for the fracture to grow out of the zone of productive interest and proceed into a zone of non-productive interest, including zones containing water. Most often, such problem areas are associated with non-productive fracture growth below the zone of productive interest. Many different approaches have been used to minimize or avoid the occurrence of such phenomena including the development of modified perforating schemes and reduction in treatment rates. Another approach has been to use a fracturing fluid which carries a heavy proppant, such as sand. Such methods do not however provide a satisfactory solution to the production of unwanted water.
The problem of undesirable fracture height growth may particularly be a problem when practicing slickwater treatments, in light of the poor transport properties of slickwater fluids which allow proppants to settle, forming a “proppant bank” at the bottom of the created fracture. Unfortunately, such proppant banks in contact with water producing zones often provide a high permeability conduit for unwanted water production. A need exists to mitigate such occurrences.